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Travelling in London during hot weather

  • carry water with you at all times, to stay hydrated 

  • don't board a train or bus if you feel unwell 

  • if you feel unwell, please get off at the next stop and contact a member of staff at the next station or speak to the bus driver 

  • during periods of very hot weather, consider retiming journeys to less busy times where possible.

Heat exhaustion and heatstroke

Heat exhaustion occurs when the body overheats and cannot cool down. Heat exhaustion does not usually need emergency medical attention if you cool down within 30 minutes. If you do not take action to cool down, heat exhaustion can lead to heatstroke which is more dangerous.  

Common symptoms of heat exhaustion include: 

  • tiredness 

  • weakness 

  • feeling faint 

  • headache 

  • muscle cramps 

  • feeling or being sick 

  • heavy sweating 

  • intense thirst 

Heatstroke is where the body is no longer able to cool down and the body temperature becomes dangerously high. 

Common symptoms of heatstroke include: 

  • confusion 

  • lack of co-ordination 

  • fast heartbeat 

  • fast breathing or shortness of breath 

  • hot skin that is not sweating 

  • seizures 

Heatstroke is a medical emergency. If you think someone has heatstroke you should dial 999 and then try to cool them down. 

While anyone can become unwell if they become too hot, there are certain factors that increase an individual’s risk during a heatwave.  These include: 

  • older people – especially those aged over 65 

  • babies and children under 5 years of age 

  • people with underlying health conditions particularly heart problems, breathing problems, dementia, diabetes, kidney disease, Parkinson’s disease, or mobility problems 

  • people on certain medications 

  • people with serious mental health problems 

  • people who are already ill and dehydrated (for example from diarrhoea and vomiting) 

  • people who experience alcohol or drug dependence 

  • people who are physically active and spend a lot of time outside such as runners, cyclists and walkers 

  • people who work in jobs that require manual labour or extensive time outside 

  • people who live alone and may rely on others for their care 

  • people living in homes which are prone to overheating, eg south facing or top floor flat 

People who are sleeping rough often have poor health and may find it especially difficult to stay cool during periods of heat. If you are concerned about someone sleeping rough, you can contact StreetLink who will support them to link to local services, including services provided during extreme heatwaves. 

People at higher risk and those who find it difficult to adapt to the heat may not always recognise the need to take extra care during hot weather.  That’s why it is important that we all keep an eye out for others 

How to cool down if you or someone else has symptoms of heat exhaustion: 

  • move to a cooler place such as a room with air conditioning or somewhere in the shade – you can use the Cool Spaces map to find somewhere close by 

  • remove all unnecessary clothing like a jacket or socks 

  • drink cool water, a sports or rehydration drink, or eat cold and water-rich foods like ice-lollies 

  • apply cool water by spray or sponge to exposed skin, and using cold packs wrapped in a cloth and put under the armpits or on the neck can also help. 

You should start to cool down and feel better within 30 minutes. 

If you are concerned about symptoms, or they are worsening, seek medical advice by contacting NHS 111. In an emergency, or if you think someone has heatstroke, dial 999. 

Enjoying water safely

Swimming pools, rivers or other bodies of water can be a fun way to cool down when the weather is hot, however summer months are also associated with an increase in drowning accidents. 

The following advice can help to keep you safe when swimming: 

  • be aware that open water can be much colder than it looks which can lead to cold water shock 

  • never enter the water after drinking alcohol 

  • wear a buoyancy aid or life jacket if you are doing an activity out on the water or at the water’s edge such as boating or fishing 

  • get out of the water as soon as you start to feel cold 

  • always look for warning and guidance signs 

  • only enter the water in areas with lifeguard cover 

  • swim parallel with the shore, not away from it 

  • always go swimming with someone else so you can help each other out 

  • check Swimfo to look up details of a designated bathing water quality by name or location.

You can find more information on safe summer swimming from the Royal Life Saving Society (RLSS)

Planning ahead

Stay up to date with forecasts and alerts for London with the Met Office. 

If you, or someone you care for, is at higher risk you can sign up for the UK Health Security Agency’s Weather-Health Alert service, which will notify you by email if forecast temperatures are likely to have an impact on health. You can also sign up on behalf of someone who doesn’t have an email account or who finds it difficult to access information online.  


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